Revealing the mesoscale deformation mechanisms of titanium alloy with tri-modal microstructure is of great significance to improve its mechanical properties.In this work,the collective behavior and mecha-nisms of slip activities,slip transfer,and grain boundary sliding of tri-modal microstructure were investi-gated by the combination of quasi-in-situ tensile test,SEM,EBSD and quantitative slip trace analyses.It is found that the slip behavior presents different characteristics in the equiaxed α(αp)and lamellar α(α1)grains.Under a low level of deformation,almost all the slip deformation is governed by single basal and prismatic slips for both of αp and α1,despite small amount of-pyramidal slip exists in α1 grains.As deformation proceeds,-pyramidal and-pyramidal slip systems with high Schmid factors were activated in quantities.Specially,certain coarse prismatic slip bands were produced across both of single and colony α1 grains whose major axes tilting about 40 °-70 ° from the tensile axis.Slip trans-fer occurs at the boundaries of αp/αp and α1/β under the condition that there exists perfect alignment between two slip systems and high Schmid factors of outgoing slip system.The slip transfer across α1/βboundary can be divided into two types:straight slip transfer and deflect slip transfer with a deviation angle of 5 °-12 °,depending on the alignment of slip planes of two slip systems.The grain boundary sliding along boundaries of α1/β and αp/β was captured by covering micro-grid on tensile sample.It is found that the crystallographic orientation and the geometrical orientation related to loading axis play great roles in the occurrence of grain boundary sliding.

Yanxi Li;Pengfei Gao;Jingyue Yu;Shuo Jin;Shuqun Chen;Mei Zhan

State Key Laboratory of Solidification Processing,Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China;Key Laboratory of Advanced Functional Materials,Education Ministry of China,School of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China

材料科学技术（英文版）

[1]Yanxi Li;Pengfei Gao;Jingyue Yu;Shuo Jin;Shuqun Chen;Mei Zhan-.Mesoscale deformation mechanisms in relation with slip and grain boundary sliding in TA15 titanium alloy during tensile deformation)[J].材料科学技术（英文版）,2022(03):72-86

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